Effect of O(2')-methylation on the stability of polynucleotide helices

Abstract

The effect of ribose(O2')-methylation on the stability of (O2')-methylated polyribonucleotide helices has been studied by conformational energy calculations. The preferred orientation of the methyl group is found to further stabilize the helical phosphodiester conformation (g^-,g^-) due to the enhanced short-range interactions arising between the methyl groups and the adjacent ribose moieties. The experimentally observed increase in melting temperature of (O2')-alkylated polyribonucleotides is thus attributable to the enhanced stability of the helical backbone conformation.